Gas heater safety device



O 1951 F. DURRELL GAS HEATER SAFETY DEVICE;

4 Sheets-Sheet 1 Filed Oct. 3, 1947 I NOV. 6, 1951 DURRELL 2,574,173

GAS HEATER SAFETY DEVICE Filed Oct. 5, 1947 4 Sheets-Sheet 2 A v I INVENTOR.

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Nov. 6, 1951 L. F. DURRELL 2,574,173

GAS HEATER SAFETY DEVICE Filed Oct. 3, 1947 4 Sheets-Sheet 3 TORNEY Nov. 6, 1951 L. F. DURRELL 2,574,173

GAS HEATER SAFETY DEVICE Filed Oct. 3, 1947 4 Sheets-Sheet 4 I A 00/5 E OUR/PEL L Patented Nov. 6, 1951 UNITED STATES PATENT OFFICE 2,574,173 GAS HEATER SAFETY DEVICE Louis F. Durrell, San Antonio, flex.

Application October 3, 1947,- Serial No. 7 78,146

4 Gla ms- 1 V This invention relates to improvements in safety devices, and more particularly to an automatic cut-off for gas or other fuel fluids which isoper: able responsive to change in fluid pressure or change in temperature or operable at termination of a predetermined time period.

It is an object of this invention to provide an automatic cut-off device which may be conveniently interposed in a gas or fuel line leading to-a gas or fluid fuel stove, the device including an automatic valve whichis actuated by instrumentalities that are operable by the completion of an electrical circuit through the medium of a thermostat or a pressure change actuated device or a conventional electrical timer.

A specific object of this invention is to provide an automatic cut-off device which includes a mechanically-actuated valve that is operably interposed in a gas line leading to any type of'gas stove, means opposing the "mechanical valve-actuating means and operable to release the valve for automatic operation to cut ofi the gas for the stove, the valve-releasing means being operated by instrumentalities which are operable by the completion of an electrical circuit through the medium of a bi-metallic temperature-responsive device located adjacent the stove, or a-pressure change actuated device operably connected with the gas line leading to the stove, or bya conventional electrical timer.

It is also an object of this invention to provide a gas heater safety device of generally improved construction, whereby the device will be simple, durable and inexpensive in construction, as well as convenient, practical, serviceable and efiicient in its use.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention resides in the combination and arrangement of parts, and in the details of construction hereinafter described and claimed, it being understood that various changes in form, proportion and minor details of construction may be made within the scope of the claims without departing from the spirit or sacrificing any advantages of the invention.

For a complete disclosure of the invention, a detailed description thereof will now be given in connection with the accompanying drawings, forming part of the specification, wherein:

Figure 1 is a front elevation depicting the 'improved safety device applied to a gas stove;

Figure 2 is a plan view thereof;

Figure 3 is aperspective view ofthe thermostat;

Figure i is a composite diagrammatic perspective view of theelectrical circuit and operable componentsof the improved safety deviceg Figure 5 is a schematic wiring diagram show ing the electric circuits, switches, and other electrical elements intheir normalworking positions;

Figure 6is a-schematicwiring diagram disclosing the electric cir'cuits established uponactu'aation of themercury switch by virtue of gas pressure failure;

Figure-7 is a schematic wiringdiagram show ing the electric circuitsestablisheduponactuation of the thermostatically controlledswitch;

Figure S'schematicallyillustrates the electric circuits established upon actuation of the electric timer switch.

Referring to the drawings; in which similar reference characters-- designate corresponding parts, It indicates-a casing for housing certain components of the safety device. This casing supports a pipe or conduit H having a control valve [2 connected therewith and secured thereto. A nipple l3-extends outwardly-from the valve l2 and this nipple is received'within a terminal of a-flexible conduitor hose l5- which has its opposed terminal connected with the conventional outlet valve or cook I6* of the usual gas supply line or pipe H, the valve l6 being controlled by manipulating a conventional operating handle 18. The other terminal of'the conduit II is provided with a nipple 20 which is received within one end of a flexible pipe-or hose 2|, and-the opposed-terminal of the hose 21'CO1 nectswith the gas cook or valve22- o f-a conventional gas stove or burner 23', In thepresent instance, a conventional gasheating stove is'depicted which provided with front'guard rails 25, but it is to be understood that the-safety device may be employed with any type gas stove or burner.

The usual rotary plug 250i the valve l2 has a valve stem 21 extending therefrom; The'valve stem is provided with aradially-iexte'nding detent'arm 28 and'a terminal reset handle or'lever 31]. A spiral torsion'spring'il has one terminal secured to the stem 21 andflits'opposedterminal anchored within the casing. Ill. The" torsion springt'l normally biases vthe'sterjn'fojr counterclockwise rotation, for a" p'urp'o'se'wh'ich' will be hereinafter stated.

The Outer minal t he etenlt' rm 281$ adapted to engage ashoulder 32- formed adjacent one terminal ofa detent lever 33 which is ivotally mounted intermediate its terminals ona p o r f l m pin 5; A. spiral to s on sp in 36 is operably interposed between the pin 35 and detent lever 33 to normally bias the lever for pivotal movement in clockwise direction, toward the detent lever 33, about its fulcrum 35, for a purpose to be hereinafter explained. The detent lever 33 is provided at its inner terminal with a downwardly extending manipulating finger 31 and an upwardly extending flange 38. A conventional solenoid 40 is positioned adjacent the flange 38 of the detent lever 33, and this solenoid is provided with an armature stem 4| which is adapted to engage the flange 38, for a purpose to be hereinafter set forth.

A conventional micro-switch 42, normally closed, has its operable projection or stem 43 located in the path of movement of the detent arm 28, and this switch is electrically connected with a conductor 45 which leads to one side of a conventional toggle switch 46. A conductor 41 leads from the opposite side of the micro-switch 42 to one side of the coil of the solenoid 40, and another conductor 48 leads from the opposite side of the coil Or solenoid 49 to one terminal 58 of a conventional transformer The transformer 5| is provided with the usual electric cord 52 adapted to be electrically connected with a conventional wall receptacle, not shown.

A Sylphon bellows 53 is connected with the pipe or conduit H and is responsive to gas pressure therein, and the outer terminal of the bellows 53 has a pin 55 extending upwardly therefrom. A switch lever 56 is pivotally mounted on a suitably supported axle 51 above the pin 55. The switch lever 56 has a counter-weight 58 secured to its outer terminal and a, conventional tiltable mercury switch 60, normally open, is secured to its inner terminal.

A standard electrical buzzer, indicated generally at 6|, is supported within the casing l0, and one side of this buzzer is electrically connected with a conductor 62, and the conductor 62 is electrically connected with one side of the toggle switch 46, which is normally closed. A conductor 63 is electrically connected with the opposite side of the electric buzzer 6| and also with the transformer 5| and conductor 48. A conductor 65 is electrically connected with the opposite side of the transformer 5| and to a binding post 66. A conductor 65a electrically connects the binding post 66 with one side of the mercury switch 68. The opposite side of the mercury switch is electrically connected with a binding post 61 through a conductor 45a.

A standard electrical timer 68 is secured within the top portion of the casing Ill, and this timer is electrically connected with the binding posts 66 and 61 through electrical conductors 19 and 1|. The timer 6!] is provided with the conventional setting handle 12 which may be manipulated in conformity with the usual practice to set the timer for actuation at the expiration of a predetermined period of time.

The conventional timer 68 is provided with the usual manually operated switch 95 (see Figures 5 to 9, inclusive) and switches 94 and 91 which are actuated by timer motor 96 at the expiration of the predetermined period.

Under non-automatic control conditions, manual switch 95 is maintained in its open, or off position, and switches 94 and 91 have been moved by motor 96 to their open positions, as shown in Figures 5 to 7, inclusive.

When it is desired to use the safety device under automatic conditions, handle 12 is turned to the desired time, closing switch 94 and opening switch 91 (see Figure 8). Manual switch 95 is sw m 4 then actuated to energize motor 96 which, on the lapse of the desired time period, closes switch 91 and opens switch 94.

The several circuits controlled by switches 95, 94, and 91 are described in detail below.

A thermostat casing 13 is preferably detachably suspended from a front rail 25 of the gas stove 23 by a suspending member or hook 15 extending upwardly from the top of the casing 13. The casing 13 is also provided with laterally extending flanges 16 adapted to engage the uprights or cross bars 25a of the front guard of the stove. By this arrangement, the casing is firmly secured to the front guard of the stove so that the components of the casing are exposed to the temperatures produced by the usual burners of the stove.

A bi-metallic or thermostatic element 11 has its outer terminal 18 anchored within the casing 13. This bi-metallic element is preferably of spiral configuration and has a trip arm 88 secured to its inner terminal, and this arm extends radially with relation to the convolutions of the spiral bi-metallic element. A rock lever 8| has pivotally-supported pintles 82 extending therefrom, and one of the pintles 82 is secured to a spiral torsion spring 83 which functions to normally bias the lower terminal of the rock lever 8| into engagement with the outer terminal of the trip arm 89. The operating terminal or stem 85 of a conventional normally open micro-switch 86 is located adjacent the upper terminal of the rock lever 8|, and this micro-switch is electrically connected by conductors 81 and 88, terminating in plug 98 which is detachably connected with socket 92 which is, in turn, connected with binding posts 66 and 61.

Having described in detail the component equipment of this safety device, the operation is deemed manifest, and in this connection, reference is made specifically to Figure 5.

The operator first connects one end of conduit l5 with the gas supply line I1, and the other end thereof is then coupled with nipple I3. Flexible pipe 2| is then connected at one of its ends with nipple 28, while the other end is secured to valve 22. Valve I6 is actuated to admit gas to conduit I5, after which handle 30 is rotated clockwise to the position shown in Figure 4 and becomes interlocked behind shoulder 32 of detent lever 33. 7

Gas under pressure enters line and actuates pin (due to expansion of bellows 53) to rotate arm 56 in such a manner as to open mercury switch 69 (see Figure 5). Gas burner valve 22 is then opened to admit gas to burner 23. The combustible gas is ignited by any suitable well known means.

Casing 13 containing the thermostatically controlled switch 86 is thereafter mounted on the stove by means of the hook element 15, and is placed in close adjacency to burner 23. When the thermostatic element 11 has been heated sumciently, arm 89 will rotate counter-clockwise (Figure 3) direction to rotate rock lever 8| in a clockwise direction against the influence of torsion spring 83. In so moving, stem of microswitch 86 is moved inwardly to open its contacts, as shown in Figure 5. Plug 90, connected with lines 81, 88 is then connected with its complementary socket 92 on casing l0. Socket 99 is connected with binding posts 66, 61, as shown in Figure 4.

The electric timer manual switch 95 is checked "7 5 to make certain it is in its open or off position,

amineand thereafter, cable 52 is; connected? with. the powersupply to energize transformer. 5L1

Toggle switch 46.;ischecked tomake certain it is closed. With this last operation, thesafety device is as shown. in Figure .4; and the elect Q circuits are as shown in-Figure 5'.

Now let it be assumed: that gaspressuresin conduit. H falls below normal. Immediately;be1-.- lows 5.3: contracts to lower pin 55', tilting lever arm fifito close mercury switchfifl. This establishes an electric circuit from transformer 51 through line 65, binding post 66, wire 65a, across mercury Switch l n 45a, binding-post 5!. wire .45; ac oss the. normally closed microeswitch 42, Wire fl; through solenoid 40.. and wire: 48:11.0. theother side of thesecondary of transformer-5;].

In completing this circuit; solenoid 140 .hasbeen ene g zed, th reby actuating. armature stem 41, whereby it. engages against flange 38 to. pivotdetent lever arm 33 on pin Biagainstthe tension of torsion spring 35. In so movinadetent lever arm 33, moves shoulder 32 away from: detent arm 23 to permit it to rotate counter-clockwise with shaft 21 under the influence of spring 3!, thereby efiecting a closure of valve IZ-and cutting oil? the supply of gas to burner 23.

Detent arm 28, rota-tingon shaft 21,,engages against projection43 of micro-switch 42, open: ing its contacts and breaking the circuitthrough solenoid 40, preventing the solenoid from burning out.

Upon deenergization of solenoid 40, armature stem 4! retracts to permit detent lever arm 33 to rotate to its normal position under. the influence of spring 36.

From Figure 5, it is also evident that a second circuit is established whenmercury switch 69 is closed. The circuit may betracedfrom transe former, 5|, wire 65, bindingpost 66, across mercury switch 60, wire 45c, binding. post 57, wire 45, across the normally closed toggle switch 45, wire 62, through the component elements of buzzer Si, wire 63, and back to transformer 5i. Buzzer 6| having thus been energized, continues torsound an audible alarm until toggle switch 45 is opened by the operator.

The position of the switches is now as is shcwn in Figure 6.

t is now ma i s h ev n t ormal a p s should e r store in c nd 1 n9 gas will flow to the burner-Z3 until handle .30 has bee o a d. k-w e e P9 ti9n shown in Figurei, thereby preventing accidents attendant on the. discharge of unignited gas.

In the event normal gas pressure hasnot been achieved at the time the operator becomes aware of the alarm, any attempt to reignite low; pres-. sure s a the urne 23 b r ta in handle 3!? to the position shown in Figu're 4 Will meet with failure as, mercury switch 60 remains closed to energize the aforementioned solenoid circuit whereby shoulder 32 is moved from its loo g engagement with detent lever arm 33 to perrnit sh t-2 its escape and subsequent rotation with to close valve [2. I

Assuming that normal pressurehas been restored and the buzzer is still sounding an alarm, toggle switch 46 is opened to, break the buzzer circuit, handle 30 is rotatedclockwise to the position shown in Figure 4, detent lever arm 28- heing passed and locked behind shoulder 32. Pressure inconduit ll again being normal, operates hellows-53 and stem 55 to rock mercury-switch 60 t i s p n p s onog l s it h hen closed and the electric'circuits are, again-, as show-nip F ur 5- Figure: 7 shows the... condition. of. the; electric circuits in. the eventrthezfiame. at: the burneris extinguished accidentally for reasons other than gas pressure: failure. In this event, element 11 cools and rotates arm countereclockwise to permit rock-levertl. (under tension of. spring 83) to rotate against stem .85 closing micro-switch 86.

A circuit is .then' established. from transformer 51 (see. Figure 7'), wire. 65, bindingpost 66, wire 81,.across micro-switch 86, wire.88, binding post 61, wire. 45,.across switch 42, wire 41, through solenoid, and wire 48, to: the other. side of transformer 5 I;

Againtthe solenoid .has been energizedto expel armature. stem 4| which engages'shoulder 3B of detent. lever 33, toreleasedetent lever arm 28 from behind shoulder 32.. Shaft 2-1 isnow free torotate, closing valve. I2' and carrying detent lever. arm into engagement with stem 43 of microsswitch 42., breaking the. circuit there, through.

The buzzer alarm circuit is also instantly established leading from transformer 5!, wire 65, binding post 66, wire. 81, across micro-switch 85, wire 88, binding postBl, wire 45, across toggle switch 46, wire 62, through the elements of buzz-er 6:, and wire 63, to the other. side of transformer 5 The operator, upon becoming aware of' the alarm, opens toggle switch .46, breaking the circuit to buzzer 6|. Cause for theextinguishment of the burner flame is then ascertained and cor: rected. Plug..90.is removed from socket 92, han dle 30 is againdepressedtothe position shown in Figure 4, gas is reignitedat burnerv 23, and toggle switch 46 is closed; After the thermoestatic element has been. heated. to the proper temperature, as described-above, plug is reinserted in socket 92. The circuits and apparatus are thus reestablished to. the conditions shown in Figures 4 and 5.

It is pointed out that in the event sufiicient time lapses-between the failure of gas pressure and the discovery thereof to permitthermostatic element TI to cool whereby switch 86 is closed, it is necessary to disconnect lug. 90 from its associated socket 92 and preheat the element before reinserting plug9il in its complementary socket 92, as just described.

Throughout the foregoing discussion, it has be-v come evident that it is unnecessary for the electric. timer 68 to have been rendered operative in order that the positively operating temperature and pressure. safety devices should become effective. As an additional feature of this invention, however, the electric timer is provided for convenience,.but subject to control by the aforementioned safety pressure and temperature re-. sponsive devices.

I The timer is conventional in construction, comprising a manually operated switch connected in series with the motor driven switches 94 and 9].. The last namedswitches are operable under the control of timersetting handle 12.

In utilizing this feature of the invention, timer handle 12 is set to the desired time, opening switch 9] and closing motor switch 94 (see Figure 8). Manually operated switch 95 is then closed to start timer motor 96, the circuit reading from transformer .5 l, wire 65, binding post 65, wire I I, across manual switch 95, wire 1 la, wire 98, across switch 94, wire illlL through motor 96, wire Hi4, and wire 63, back to the other side of trans.- term ni-5| At the expiration of the predetermined time in-. terre rmoter d ives and. open the mo switch 94, thereby deenergi'zing the former, and simultaneously therewith closing switch 91. Closing of switch 9! establishes a new circuit readin from transformer 5|, wire E5, binding post 66, wire ll, across switch 95, wire Ila, across switch 91, wire 10, binding post 61, wire 45, across microswitch 42, wire 41, through solenoid 40, and wire 48, to the other side of the transformer 5|.

The solenoid, being energized, acts as before to expel armature stem 4| to engage against shoulder 38, rotating detent lever 33 to release detent lever arm 28 from behind shoulder 32, whereby shaft 21 rotates to close valve l2 and to cause engagement of detent lever arm 28 against stem 43 of micro-switch 42. This breaks the circuit to the solenoid, as described above, to prevent its burning out.

It should now be clear that expiration of the predetermined time interval will cause switch 94 of the electric timer to be opened, and switch 91 to be closed as set forth hereinabove. The buzzer 8| will then be sounded by a completed circuit through wire 65, binding post 66, wire H, across switch 95, wire Ila, across switch 91, wire I0, binding post 61, wire 45, across switch 46, through buzzer GI, and wire 63, back to the other side of transformer 5|. The buzzer may be silenced by opening either of manual switches 95 or 46.

To summarize the operation of the safety device described above, the supply of gas to a stove incorporating said safety device may be cut off upon a. deficiency of gas pressure, upon the expiration of a time interval as determined by the electric timer, or upon cooling of a bi-metallic switch element due to inadvertent extinguishing of the flame inside the furnace or stove.

In addition to the above gas cut-off safeties, a buzzer is sounded whenever any of the emergencies cited may arise.

It is readily apparent, therefore, that a safety device has been invented which not only prevents a source of danger in the form of free gas, but also serves notice to the operator that a situation has arisen which requires immediate attention if the stove is to be restored to normal heating condition.

Having described my invention in detail, it is to be understood that the invention is not to be limited to the modifications described and illustrated herein, but only by the scope of the appended claims.

Having thus described my invention as new and useful, what I claim is:

1. A safety device in combination with a gas line and a gas burner to which gas under pressure is supplied through the gas line, a valve operably located in the gas line, means for normally biasing the valve towards closed position, a yieldable detent adapted to engage and hold the valve in open position, an electric circuit including a solenoid adapted to operably engage the detent, an electric switch electrically connected to a source of electric current supply and to the solenoid, pressure-responsive means communicated with the gas line and operable to close the switch when pressure drops in the gas line, thereby establishing an electric circuit to the solenoid whereby the solenoid actuates the detent to release the valve for closing to cut off the gas supply to the burner, and timer mechanism electrically connected with the circuit including said solenoid to independently operate the switch upon lapse of a predetermined time.

2. A safety device in combination with a gas line and a gas burner to which gas underpresoperably located'in the gas line, means for normally biasing the valve towards closed position, a yieldable detent adapted to engage and hold the valve in open position, an electric circuit including a solenoid adapted to operably engage the detent, an electric switch electrically connected to a source of electric current supply and to the solenoid, pressure-responsive means communicated with the gas line and operable to close the switch when pressure drops in the gas line, thereby establishing an electric circuit to the solenoid whereby the solenoid actuates the detent to release the valve for closing to cut off the gas supply to the burner, a thermostat located adjacent the gas burner and operable to establish independently an electric circuit to the solenoid when the temperature drops thereby releasing the valve for closing to cut off the gas supply independent of the gas pressure in the line, and a timer mechanism connected in said circuit including said solenoid and independently operating said switch upon lapse of a predetermined time.

3. A safety device in combination with a gas line and a gas burner to which gas under pressure is supplied through a gas line, a valve operably located in the gas line, means for normally biasing the valve towards closed position, a yieldable detent adapted to engage and hold the valve in open position, a solenoid adapted to operably engage the detent, an electric switch electrically connected to a source of electric current supply and to the solenoid, pressure-responsive means communicated with the gas line and operable to close the switch when pressure drops in the gas line, thereby establishing an electric circuit to the solenoid whereby the solenoid actuates the detent to release the valve for closing to cut 011 the gas supply to the burner, a thermostat located adj acent the gas burner and operable to establish an electric circuit to the solenoid when the temperature drops thereby releasing the valve for closing to cut off the gas supply independently of the gas pressure in the line, and an electric timer operable to establish an electric circuit to the solenoid at the expiration of a predetermined period of time thereby releasing the valve for closing to cut off the gas supply independently of the gas pressure in the line or temperature at the thermostat.

4. A safety device in combination with a gas line and a gas burner to which gas under pressure is supplied through a gas line, a valve operably located in the gas line, means for normally biasing the valve towards closed position, a yieldable detent adapted to engage and hold the valve in open position, a solenoid adapted to operably engage the detent, an electric switch electrically connected to a source of electric current supply and to the solenoid, pressure-responsive means communicated with the gas line and operable to close the switch when pressure drops in the gas line, thereby establishing an electric circuit to the solenoid whereby the solenoid actuates the detent to release the valve for closing to cut off the gas supply to the burner, and an electric timer operable to establish an electric circuit to the solenoid at the expiration of a predetermined period of time thereby releasing the valve for closing to cut off the gas supply independently of the gas pressure in the line.

5. A safety device in combination with a gas line and a gas burner to which gas under pressure is supplied through a gas line, a valve operably located in the gas line, means for norsure is supplied through the gas line, a valve mally biasing the valve towards closed position,

a detent arm" movable: with; "the valveya yieldable: detent lever adapted to: engage the: vd'etent arm to hold'thez valve; inropensxposition, a. solenoid adapted to; operably engage. the detent: lever, a tiltableimercury. switch; normally .biased towards. open position; and. electrically connectedrto :asource of" electric; current :supplyan'dt t'ot the-sole:- noid, a normallytclosed. bellows communicated with the gas line. and: op'erable whenxopen .responsive to gas pressure in the rline to engage and hold .the mercury switch 'in' 'openiposition: :and: also operable:tordisengagethe mercury'switchte permit it to tilt to cl'osed -position. when pressure: drops in the gas liner-therebyestablishingan-"electric circuitto the solenoid whereby the solenoid actuates the'detentlever to:liberateithez-valvesforclosing to cut-off the-:gas supply to the: burner; and :a normally closed-switch interposed in the electrical connectionbetween thermercury switch and the solenoid and operablypositionedin the path'of movement of the detent-arm whereby the arm engages andropens' the-switch'after the-valve has moved to closed positionthereby breaking the electric circuit to the solenoid after the gas has been cut off.

6. A safety device in: combination with-a gas line and a gas burner-towhich: gasz-under'pressure is suppliedthrough. a gas?v line; a valve. operably located in the gas :line, -means for"normally=biasing the valve towardsyclosed.position adetent armmovable with "the valve, a yieldable detent lever' adapted to engage the: detentyarm to hold the valve in .open position, :a solenoid adaptedwto operably engagethedetent lever, a; tiltable mercuryswitch normally biased-towards open: posi tion-and-electrically connected-tea source-of electric current supply and to the solenoidha normally closed bellows communicated with the gas. line and operable when open-responsive to gas pressure in the line-toengage and hold the mar-- cury switch in open position and also: operable to; disengage the mercuryswitch to permit itto tiltto closed position whenpressure drops in the. gas line thereby establishing an electriccircuit. to the solenoid whereby the solenoid actuates the detent. lever to liberate-the.valveefor closing to cut ofithe gas supply to the burner and -anormally closed switchinterposed in the electrical: connection between the: mercury switch: and the solenoid and operably- -positioned inthe path of movement of the detent. arm whereby the arm. engages and opens the-switch" after the valve: has moved to closed position thereby breaking: the electric circuit. to.-.the solenoid after the gas has been cut ofl", and an electric buzzer electrically connected irriparallelvwith the solenoid to audibly (indicate when the solenoid is actuated that the gas has been cut oil.

7. A safety device in combi'nati'onwith a gas line and a gas-burner to whichtgasrunder pressure is supplied through a gas line,, a valve operably located. in the gas line, means for normally bias.- ing the valve towards closedjposition, a. :detent arm movable with the'valve, a yieldable .detent lever adapted to engage "the detent arm to hold the valvein .openposition, a solenoid adapted. to operably engage the "detent'lever; a tiltable mercury switch normallybiased*towards open position and electrically connectedtoasource of .electric current supply and" to'the solenoicflya 'normally closed'bellowscommunicated with the "gas line and operable when open responsive to gas pressure in the line to engage and hold the mercury switch in open position and also operable to disengage the mercury switch to permit it to 10 gas line thereby establishing an electric circuit toithe solenoid wherebythe solenoid actuates the detent'lever'to liberate thevalve forclosing to cut off the gas-supplyto the'burner, a normally closed switchzinterposed in the electrical connection between the mercury switch and the solenoid and operably-positioned in the path ofmovement 01' theudetent arm whereby the arm engages and opens the switch after the valve has'moved' to closed position thereby breaking the: electric circuit to-thesolenoidafter thegas-has been cutoff, an electric buzzer electrically connected in parallel with the solenoid toaudibly indicate when the solenoid is-actuatedthat the gas has been cutoff, and an electricswitch interposed inthe' electrical 'connection'to thebuzzer whereby the buzzer may be manually silenced:

8; A- safety device in combination Witha gas. lineand a gas-burner-to whichzgasunderwpressure is supplied through a gas line; avalve operablylocated in=the-gas line, means for normally biasing thevalve towards closed position, a yieldable detentadapted toengage and hold the valvein open position, a solenoid adapted tooperably engagethe 'detent, a thermostat located adjacent the burner and-including a bi-metallic element operable responsive totemperature variation, a normally open. switch electricallyeonnected with. the solenoid, a triparm carried by the bi-metallic element and operable to close the switch when the temperature of the burner drops thereby establishing an electric circuit to the solenoid whereby. the. solenoid actuates the detent to release thevalvefor closing to cut offthegassupply.

- to. thelburnen.

.9. A safety device in combination with .a .gasv line. andv agasburner towhich gas under pres.- sure is supplied througha gas line, a. valve operably located in. the. gas line, means for normally biasing the. valve towardsclosed positioma yield-' abledetent adaptedv to engage and hold the valve. inopenposition, a..solenoid adapted to operably engage the .detent, a thermostat located adjacent thelbnrner and. including. a bi-metallic element. operable in. response. to temperature variation, a. normally closed switch electrically connected;

the solenoid, a. trip arm carried by the metallic element and. operable to close a second switch. when the temperature. of the burner drops thereby establishing an electric circuit to the solenoid whereby the. solenoid actuates the detent, to close the valve to cut oil the gassupply to. the. burnensaidl actuation of said detent subsequently operatingsaid firstswitch to. deenergizesaid sole.- noid, and a buzzer in. said circuit connects in parallel. with said second switch and-adaptedto beoperatedlby said temperature responsive ele-- mentin response to cooling thereof.

'11). .A portable safety device in combinatio witha. gas li'neand .a. gas burner to which. gas. under pressure'i's supplied through a gas line, an electric circuit including a, transformer, in combination. with a. gas, line and a normally open mercuryswitch normally open and operably connected to .apressure responsive device,.a solenoid. operable toactuate adetent, a valve interposed in saldgas. line and means. normally biasing said. valve toward closed position, a switch normally closed. interposed between said. mercury switch and-saidsolenoidandadapted to be opened upon. closing iQfUsaid'. valve through actuation. of said d'etent'by said solenoid, a manual switch normally closed and electrically connected to said mercury switch and a buzzer, which is in turn, electrically connected to said transformer, and a tilt to closed position when pressure drops in the timer having motor driven switches operable to complete a circuit between said transformer and said mercury switch, said mercury switch 'and said manual switch, said manual switch and said buzzer, and said buzzer to said transformer, whereby a warning is sounded at the expiration of a predetermined time period.

"11. A portable safety device including a gas line and a gas burner to which gas under pressure is supplied through the gas'line, comprising a-circult including a transformer for supplying current to a mercury switch normally open and operably connected to a pressure responsive device, a solenoid operable to actuate a, detent, a valve interposed in said gas line and means normally biasing said valve toward closed position, a switch normally closed interposed between said mercury switch and said solenoid and adapted to be opened upon closing of said valve through actuation of said detent by said solenoid, a manual switchnormally closed and electrically connected to said mercury switch and a buzzer, which is in turn, electrically connected to said transformer, and a timer having motor driven switches operable to complete a circuit between said transformer and said mercury switch, said mercury switchand said normally closed switch, said normallyclosed switch and said solenoid, and said solenoid and said transformer, whereby said detentreleases said valve which moves to its closed position to shut off the supply of gas at the expiration of a predetermined time period.

12. A portable safety de'vice including a. gas line and a gas burner to which, gas under pressure is supplied through the gas line, comprising a circult including a transformer for supplying current to a mercury switch normally open and ope erably connected to a pressure responsive device, aisolenoid operable to actuate a detent, a valve interposed in. said gas line and means normally biasing said valve toward closed position, a switch normally closed interposed between said mercury.

switch and said solenoid and adapted to be opened upon closing of said valve through actuation of said detent by said solenoid, a manual switch normally closed and. electrically connected to saidmercury switch and a buzzer, which is in turn, electrically connected to said manual switch and said transformer, and a timer having motor driven switches operable to complete a circuit at the expiration of a predetermined time between said transformer and said mercury switch, said mercury switch and said normally closed switch, said normally closed switch and said solenoid, said solenoid and said transformer, and said mercury switch and said normally closed switch,said normally closed switch and said buzzer, said buzzer and said transformer, whereby the solenoid is energized to actuate said detent to release said valve to move to closed position andthe buzzer is sounded at the expiration of a predetermined time period. I V

13. A portable safety device including a gas line and a gas burner to which gas under pressure is supplied through the gas line, comprising a circuit including a transformer for supplying current to a mercury switch normally open and operably connected to a pressure responsive device, a solenoid operable to actuate a detent, a valve interposed in said gas line and means normally biasing said valve toward closed position, a switch normally closed interposed between said mercury switch and said solenoid and adapted to be opened upon closing of said valve through actuation of said detent by said solenoid, a manual switch normally closed and electrically connected to said mercury switch and a buzzer which is, in turn, electrically connected to said manual switch and said transformer, a timer having switches operable to complete circuits to said solenoid and said buzzer, and a normally open micro-switch bridging said mercury switch and adapted to be closed by a temperature responsive bi-metallic element upon accidental extinguishment of the flame in said gas burner, whereby the operation of the timer switch is overridden by said microswitch in times of accidental flame extinguishment regardless of the predetermined time interval as set by said timer, and said gas is shut oil! in conjunction with the sounding of said buzzer.

14. A safety device in combination with a gas line and 'a gas burner to which gas under pressure is supplied through said gas line, a valve operably located in the gas line, means for normally biasing the valve towards closed position, a detent arm movable with the valve, a yieldable detent lever adapted to engage the detent arm to hold the valve in open'position, a solenoid adapted to operably engage' the detent lever, a tiltable mercury switch normally biased towards open position and electrically connected to a source of current supply and to the solenoid, a normally closed bellows communicating with a source of gas under pressure and operable in response to normal gas pressure to engage and hold the mercury switch in open position and also operable to disengage the mercury switch to permit it to tilt to closed position when said gas pressure drops to establish an electric circuit to the sole-' noid whereby the solenoid actuates the detent lever to liberate and close the valve to cut off the gas supply to the burner, a normally closed switch interposed in the electrical connection between the mercury switch and the solenoid and operably positioned in the path of movement of the detent arm, whereby the arm engages and opens the switch after the valve has moved to closed position, thereby breaking the electric circuit to the solenoid after the gas has been shut oil, an electric buzzer electrically connected wih said solenoidaL'and an electric timer in said last-mentioned electrical connection adapted to simultaneously operate said buzzer and said solenoid at the expiration of a predetermined interval of time.

' LOUIS F. DURRELL.

REFERENCES orrm) The following references are of record in the file of this patent: 

